Post challenge variability in time gap pertaining to appearance of Toxoplasma gondii DNA in blood and appearance of visible clinical signs in murine model

A marked variation, in terms of time lag gap of the depiction of visible clinical signs and the actual appearance of parasitic stages in body tissues, exists in experimental toxoplasmosis. Keeping this in mind, a study was designed to find out the time gap associated variability in appearance of tachyzoites in blood stream of infected mice. For this purpose, surface antigen 3 (SAG 3) was selected as a candidate to detect toxoplasmosis from blood samples taken at regular intervals from murine models. PCR was standardized to diagnose toxoplasmosis in ten inbred Swiss albino mice after experimental inoculation of 100 tachyzoites of laboratory maintained human RH strain of the parasite. The blood samples were subjected to PCR, in duplicates, using primers directed to the multicopy of SAG 3 gene at regular 12 -h interval post infection. The tachyzoites begin to appear between 36 h post infection and by 48 h blood of all the mice were found to be infected by tachyzoites. Alongside, other visible symptoms begin to appear after 72 h post infection. In conclusion, ample time gap was found regarding the initiation of clinical infection and actual appearance of visible clinical signs that could prove detrimental in final outcome of condition.